From: Nadav Amit <namit@vmware.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Sasha Levin <sashal@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>, X86 ML <x86@kernel.org>,
Juergen Gross <jgross@suse.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
Linux Virtualization <virtualization@lists.linux-foundation.org>,
KVM <kvm@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently
Date: Tue, 16 Feb 2021 19:17:54 +0000 [thread overview]
Message-ID: <AFA552C0-88B1-4D58-B3C5-1A571DBF0EA6@vmware.com> (raw)
In-Reply-To: <YCu2MQFdV4JTrUQb@hirez.programming.kicks-ass.net>
> On Feb 16, 2021, at 4:10 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, Feb 09, 2021 at 02:16:49PM -0800, Nadav Amit wrote:
>> @@ -816,8 +821,8 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>> * doing a speculative memory access.
>> */
>> if (info->freed_tables) {
>> - smp_call_function_many(cpumask, flush_tlb_func,
>> - (void *)info, 1);
>> + on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
>> + cpumask);
>> } else {
>> /*
>> * Although we could have used on_each_cpu_cond_mask(),
>> @@ -844,14 +849,15 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
>> if (tlb_is_not_lazy(cpu))
>> __cpumask_set_cpu(cpu, cond_cpumask);
>> }
>> - smp_call_function_many(cond_cpumask, flush_tlb_func, (void *)info, 1);
>> + on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
>> + cpumask);
>> }
>> }
>
> Surely on_each_cpu_mask() is more appropriate? There the compiler can do
> the NULL propagation because it's on the same TU.
>
> --- a/arch/x86/mm/tlb.c
> +++ b/arch/x86/mm/tlb.c
> @@ -821,8 +821,7 @@ STATIC_NOPV void native_flush_tlb_multi(
> * doing a speculative memory access.
> */
> if (info->freed_tables) {
> - on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> - cpumask);
> + on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
> } else {
> /*
> * Although we could have used on_each_cpu_cond_mask(),
> @@ -849,8 +848,7 @@ STATIC_NOPV void native_flush_tlb_multi(
> if (tlb_is_not_lazy(cpu))
> __cpumask_set_cpu(cpu, cond_cpumask);
> }
> - on_each_cpu_cond_mask(NULL, flush_tlb_func, (void *)info, true,
> - cpumask);
> + on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
> }
> }
Indeed, and there is actually an additional bug - I used cpumask in the
second on_each_cpu_cond_mask() instead of cond_cpumask.
next prev parent reply other threads:[~2021-02-16 19:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 22:16 [PATCH v5 0/8] x86/tlb: Concurrent TLB flushes Nadav Amit
2021-02-09 22:16 ` [PATCH v5 4/8] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2021-02-16 12:10 ` Peter Zijlstra
2021-02-16 19:17 ` Nadav Amit [this message]
2021-02-18 8:14 ` Christoph Hellwig
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